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Looking to lighten up an Ultegra Di2 Group. This is on a race bike, hence based on recent experience it is highly probably that it will be crashed hard at least once during the season, hence Ultegra rather than Dura Ace Di2, hence I don't want to be putting anything too exotic on it.

Obviously need to retain shifters, derailleurs, wiring etc...

I am thinking Dura ace Cassette would be a good start, cranks /BB... surely lots of opportunity here, even the Sram Red exogram I have on another bike is a hell of a lot lighter than the Ultegra one. Brake Calipers are another area. Perhaps Zero G ? KCNC ? Or the Planet X CNC ones - although I didn't have much luck keeping the forged versions centered on a previous bike.

Any suggestions ? The key would be to not comprimise shift performance and I don't know how sensitive the Di2 is to cranks not as stiff as the Shimano ones.

Another option as well is the new 9070 di2 is compatible with the ultegra di2 based on the new cable system, so whereas the 7970 wasn't, the 9070 is, so the actual di2 shifters, front/rear mechs can be integrated, providing you buy 10/11 speed obviously to suit.

There's a bit more weight shaved there if you've got the money? Soon though you'd have the dura ace di2 by upgrading parts.

Planet x brakes seem to flex well and become uncentered easily i found. What about the new sram red brakes, failing that, just go get some gravitas's and be done with it?

I would be careful messing with the brakes too much, in particular if your racing includes wet weather (which your "Ireland" location suggests).

Generally the drivetrain is probably not the most cost-effective place to shed weight. Crank can go some way, of course, SRAM 2013 with aftermarket rings is rather light and not outrageously expensive.

I installed DA7900 brakes and crankset with my Ultegra Di2 parts. That combined with a DA cassette or a Sram Red cassette will help with the weight. I went with DA cassettes since I feel they shift a bit better and I can use them on my CX bikes. Although the new Red cassettes look nice.

You could drop more weight by going to a lighter crankset, but you're not talking about a lot of savings unless you're willing to spend lots of money.... in which case you might not be looking at the Ultegra anyhow

cllrhodgen wrote:Another option as well is the new 9070 di2 is compatible with the ultegra di2 based on the new cable system, so whereas the 7970 wasn't, the 9070 is, so the actual di2 shifters, front/rear mechs can be integrated, providing you buy 10/11 speed obviously to suit.

There's a bit more weight shaved there if you've got the money? Soon though you'd have the dura ace di2 by upgrading parts.

Planet x brakes seem to flex well and become uncentered easily i found. What about the new sram red brakes, failing that, just go get some gravitas's and be done with it?

Given the price of 9070 shifters, I wouldn't swap them even if they weighted 0 grams. When you crash, you lose big time.